Review on Timetec 8GB KIT (2x4GB) - DDR3 1067MHz/1066MHz PC3-8500 CL7 SODIMM Memory MAC RAM Upgrade - Compatible with Apple Mac Book, Mac Book Pro, iMac, Mac Mini (Late 2008, Early/Mid/Late 2009, Mid 2010) by Joseph Campbell

I purchased this RAM upgrade after installing my wife's Late 2012 MacMini, which greatly improved performance. In this case, we replaced the factory-installed 4GB with 16GB, which is a 4x increase. The operation went from sluggish to lightning fast. It was like day and night. About 5 years ago I upgraded my iMac from the factory 4GB to 12GB at the end of 2009. But when RAM prices dropped, I decided to bump it up to 16GB. This will be a 1.33x increase. My first attempt failed. But after two more tries I got it right and the computer works great. Here are the lessons we learned hoping they will help others. The four memory slots on this iMac are located on the bottom of the case, just below the Apple logo. You turn off the computer, unplug it, spread a towel on your work surface, and lay the computer face down on the towel. Lifting the adjustable base reveals a small rectangular panel with ventilation holes. Wrap a wrist strap around your wrist, loosen the three captive Phillips screws on the plate, and expose four memory cards. My vent panel and the visible edge of the RAM cards were covered in dust so it was time to clean them first. Removing RAM cards is a bit trickier than most modern computers with fold-out slots. Each of the two pairs of memory slots is wrapped in a plastic latch that looks like shiny black tape. Pull the tab out so one end is free and pull. Don't be afraid to apply pressure until you hear a click and see the two paired memory cards pull toward you about an eighth to a quarter of an inch. Cards you want to replace. In my case, there were two spare Crucial-branded 4GB memory cards in the bottom (i.e., front) slots, and two original 2GB MAC cards in the top slots. I replaced the latter with my pair of new 4GB Timetec RAM cards. After inserting new cards and screwing the cover back on, I reconnected the iMAC as a test. Disappointment! A dark screen and a series of very scary loud beeps lasting several seconds. The beeps continue, not three like one of the descriptions I've read. Time to google the problem. The best advice I could find was that the new memory cards, or at least one of them, is probably faulty. Now I'm wondering why I bothered to do this in the first place as the computer was working fine before I attempted the update. But with no other options I decided to reinstall the original MAC 2GB cards. I turned off the machine, opened the lid again, and put the old cards back in. When I turned the car back on, the infernal squeaking sounded again. Now I've really cursed myself. Have I destroyed a great computer, my favorite workhorse, for an unnecessary upgrade? Time to calm down and think things through. I turned off the computer, unplugged it, and reopened the RAM slot. Now it dawned on me. I've had trouble replacing the cap the last two times. Perhaps the memory cards have not been fully inserted? After fiddling with it a bit, I felt one of the old replacement cards in the bottom slot push harder on one side so the front edge of the card was flush with the edge of the slot. After a few more squeezes and wiggles, I got the other side of that card to blink as well. It took a lot of convincing, more than I was willing to try on my first two install attempts. Soon, using a large plastic spatula, I installed all the cards flush. This time the hat was much easier to put on and I felt good. Powered back on, restarted machine and voila! Everything worked. . . . . Pooh. The project is successful. Hope this can help someone with a similar problem.